Selective area growth of InP on lithography-free, nanopatterned GaAs(001) by metalorganic chemical vapor deposition

Abstract

The authors have demonstrated the feasibility and principle of utilizing silica nanospheres (SNSs) as a pattern for selective area growth of metamorphic InP on GaAs(001) substrate. SNSs with the average diameter of ∼460 nm were uniformly and closely distributed on GaAs by spin-coating. The hexagonal array of the SNSs is monolayer, which acts as a nanosphere pattern with high aspect ratio. Nearly 2-μm-thick InP epitaxial layer was deposited through the intersphere spaces using conventional two-step growth by low-pressure metalorganic chemical vapor deposition. The complete coalescence of metamorphic InP over SNSs has been achieved via the epitaxial lateral overgrowth. Cross-sectional transmission electron microscopy demonstrates that threading dislocations caused by the lattice mismatch (∼3.8%) between InP and GaAs have been blocked by SNSs. X-ray diffraction exhibits a reduction in the full width at half-maximum of InP grown on nanosphere-patterned GaAs as compared with the corresponding growth on nonpatterned GaAs. Therefore, the crystalline quality of metamorphic InP is highly improved in spite of some still existing dislocations.